If the terrain elevation is 1,295 feet MSL, what is the height above ground level of the base of the ceiling?

To determine the height above ground level (AGL) of the base of the ceiling, one must subtract the terrain elevation from the altitude of the ceiling. In this case, if the ceiling is reported at an altitude of 1,800 feet mean sea level (MSL), the calculation would be as follows:

1. Ceiling altitude at 1,800 feet MSL.

2. Terrain elevation at 1,295 feet MSL.

By subtracting the terrain elevation from the ceiling altitude:

1,800 feet MSL (ceiling) - 1,295 feet MSL (terrain) = 505 feet AGL.

This calculation shows that the base of the ceiling is 505 feet above the ground level at the terrain elevation stated. Understanding this type of altitude measurement is crucial for pilots, as it directly affects how they navigate and ensure safe clearance from the terrain while flying.